1. Field of the Invention
The present invention relates to a printer and, more particularly, to a printing paper guiding method and apparatus for a printer that performs printing over the entire sheet of printing paper as a printing head of the printer pushes the printing paper onto a drum.
2. Description of the Related Art
There are various methods for printing image data on printing paper. For example, a thermal printer performs a printing on printing paper located in the lower portion of an ink film, by employing a thermal print head for generating heat responsive to image data, and the ink film located under the lower portion of the thermal print head. Specifically, a color type thermal transfer printer repeatedly performs printing three times for the divided images such as yellow, magenta and cyan, in order to realize full coloring. Such a thermal transfer printer is an apparatus for sublimating or melting the ink of the ink film to which the heat of a thermal print head is delivered so as to perform a printing on printing paper. The image printed as above is as clear as a photograph taken by an ordinary camera.
Accordingly, the thermal printer can be utilized for various fields. For example, an image is input to a computer by employing an image input device, for example, a scanner, and the input image is modified and synthesized by employing a computer program. Thus, a new image is constituted and outputted again, or imaginary scenes are reproduced and outputted by using a computer graphics method, or an image of an electron microscope is converted into image data which is outputted with a photograph-like image quality. Recently, such precision thermal transfer printers are being used in lieu of photographic printers. Accordingly, the output of such devices should be of nearly the same image quality and form as a photograph from a camera.
FIG. 1 is a side elevation showing a printing operation of a color thermal transfer printer adopting the conventional printing method. A printing paper 9 provided by a paper supply cassette 1 is guided by paper supply rollers 3 and provided between a paper reject/supply roller 2 and a drum 10. The provided paper 9 is pushed onto the drum 10 by a plurality of guide rollers 4 that exist around the drum, and as drum 10 rotates, the leading end of the pushed printing paper 9 reaches an initial printing location 11 where a printing at the lower portion of printing head 8 is performed initially. At this time, the leading end of the printing paper is separated from the drum.
As shown in FIG. 2, when a printing is performed from the leading end of the printing paper by lowering the printing head 8, a problem occurs in that guide rollers 4 cannot push the printing paper 9 onto drum 10 thoroughly. Thus, printing cannot be performed throughout the entire sheet of printing paper, and the printing may be disturbed. As a result, image quality is degraded.